Discussion

This variety seems to be one of the consistent elements in the flora of forest on the slopes of ultrabasic hills up to c 500 m altitude. It is abundant on Bukit Silam. The short petiole and absence of reflexed leaflets most easily distinguish it from the type variety, though there are several other distinguishing features. (J. Dransfield, The Rattans of Sabah. Sabah Forest Records 13.. 1984)D

Discussion

C. laevigatus var. mucronatus is one of the most slender species of rattan in Brunei; it has a very dark colour when fresh, but dries pale green. It is usually found on ridge tops on rather poor soils at altitudes up to 900 m above sea level. (J. Dransfield, The Rattans of Brunei Darussalam. 1997)E

Uses

Description

Very slender solitary rattan climbing to great heights, often over 60 m in length; stem without sheaths c. 4 mm diam., with sheaths to 8 mm diam.; internodes to 13 cm, frequently less in exposed stems. Sheaths dull dark green with very few triangular spines to 3 mm, often with wart-like bases; knee well developed; ocrea to 3 mm fringed with hairs. Leaf cirrate to 90 cm including the cirrus to 45 cm, often the whole leaf to only 30 cm in exposed stems; petiole absent or very short, c. 1 cm; leaflets c. 8 on each side of the rachis, lanceolate and abruptly narrowed at the tip, irregularly arranged in pairs or singly, the basal 1 or 2 reflexed across the stem, the longest to 13 × 2 cm, dark green (drying pale), ± cucullate, transverse veinlets conspicuous. Inflorescences without terminal flagellum, to 45 cm with c. 8 partial inflorescences in all, in detail very similar to that of the type variety but much smaller. Mature fruit ovoid (? always), c. 15 × 10 mm, with a short beak and covered with 14 vertical rows of straw-coloured scales with darker margins. Seed ovoid c. 12 × 8 mm; endosperm deeply ruminate. Seedling leaf bifid. (Fig. 36). (J. Dransfield, The Rattans of Brunei Darussalam. 1997)E

Discussion

C. laevigatus var. laevigatus is a very widespread species occurring at altitudes up to 850 m above sea level and on a variety of soils. This is a very variable taxon. Some forms have very narrow leaflets. This species can easily be seen from the Labi Road in Andulau Forest Reserve. (J. Dransfield, The Rattans of Brunei Darussalam. 1997)F

Discussion

In the protologue this variety was diagnosed on the basis of the slightly grouped uppermost and lowermost leaflets, the petiole, rachis and sheath with dense brown indumentum and the smaller fruit. One specimen from the protologue, Xu, Y & Zhang, YE Z. 14327, does not fit the diagnosis and we place it in the nominate variety, whilst Chen, S. Y. & Yu, C. 6471 (also cited by Pei et al. 1989) was not seen. Grouped lower leaflets and extensive, dense, dark indumentum are not shown by specimens placed in the nominate variety, but the relevant part of the rachis is seldom preserved in any case. The type specimen of this variety has no fruit and the fruits of two others in the original description are not especially small, so we suggest that this character be disregarded. Although maintained here it seems likely that fuller field observations will show that the two varieties given here are synonymous, their apparent distinctness resulting from individual variation combined with collection of fragmentary material. For example, leaflet grouping is often seen in Calamus species on leaves from near the base of the stem even when the leaflets on upper leaves are regularly arranged (personal observations); it is particularly tempting to collect such unrepresentative leaves on a plant as huge as C. flagellum. Furthermore, indumentum tends to be thickest on young stems and freshly emerged organs, thinning out later. (T. Evans & K. Sengdala & B. Thammavong & O.V. Viengkham & J. Dransfield, A Synopsis of the Rattans (Arecaceae: Calamoideae) of Laos and Neighbouring Parts of Indochina. 2002)G